Abstract: Provided is a camera module that is capable of driving with low power consumption and is small-sized and thin even in a case of having high resolution. A movable portion (4) provided in a lens driving device (9) of a camera module (20) has a shape that covers an upper side of a fixed lens (1b) and at least a part of a side part (side surface) of the fixed lens (1b).

Abstract: Provided is a photographing apparatus having both a phase difference auto-focusing function and a contrast auto-focusing function. Provided is an auxiliary light projector capable of projecting auxiliary light of a pattern suitable for the photographing apparatus. An auxiliary light projector and a photographing apparatus including the auxiliary light projector according to an embodiment of the present disclosure may reduce an auto-focusing time with respect to an object and improve reliability of an auto-focusing function.

Abstract: A three-piece infrared single wavelength lens system includes, in order from the object side to the image side: a stop, a first lens element with a positive refractive power, a second lens element with a positive refractive power, and a third lens element with a positive refractive power. The focal length of the first lens element is f1, the focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: 0.5<f1/f23<1.0. When the above relation is satisfied, a wide field of view can be obtained and the resolution can be improved evidently.

Abstract: A four-piece infrared single wavelength lens system includes, in order from the object side to the image side: a first lens element with a refractive power, a stop, a second lens element with a positive refractive power, a third lens element with a positive refractive power, and a fourth lens element with a positive refractive power. The focal length of the first lens element is f1, the focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: ?210<f1/f23<365. When the above relation is satisfied, a wide field of view can be obtained and the resolution can be improved evidently.

Abstract: A four-piece infrared single wavelength lens system includes, in order from the object side to the image side: a first lens element with a positive refractive power, a stop, a second lens element with a refractive power, a third lens element with a positive refractive power, and a fourth lens element with a negative refractive power. The focal length of the first lens element is f1, the focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: 0.05<f1/f23<1.8. When the above relation is satisfied, a wide field of view can be obtained and the resolution can be improved evidently.

Abstract: An optical lens assembly, which has an optical axis, includes, at least one dual molded lens element having two plastic parts with different colors. The dual molded lens element includes a transparent portion and a light absorbing portion, wherein the transparent portion has an optical effective region. The dual molded lens element has an outer diameter surface connecting a first side surface and a second side surface of the dual molded lens element, the transparent portion is arranged from an optical effective region of the dual molded lens element to the outer diameter surface and to surrounds the dual molded lens element, thus the transparent portion is a part of the outer diameter surface, and the light absorbing portion is located on one of the first side surface and the second side surface of the dual molded lens element.

Abstract: Provided is an interactive lens assembly, including first lens, a second lens, an aperture stop, a third lens and a filter from an object side of the interactive lens assembly to an image side of the interactive lens assembly in turn. The first lens is of a negative focal power, an image side surface of the first lens is concave; the second lens is of a focal power; the third lens is of a positive focal power, an image side surface of the third lens is convex, and each of the first lens, the second lens and the third lens is made of a plastic material; the interactive lens assembly meets the following formulas: (CT1+CT2)/CT3<0.9; and ImgH/(f*TTL)?0.4 mm?1.

Abstract: A six-piece optical lens for capturing image and a six-piece optical module for capturing image are provided. In order from an object side to an image side, the optical lens along the optical axis includes a first lens with refractive power, a second lens with refractive power, a third lens with refractive power, a fourth lens with refractive power, a fifth lens with refractive power and a sixth lens with refractive power. At least one of the image-side surface and object-side surface of each of the six lens elements is aspheric. The optical lens can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: A six-piece optical lens for capturing image and a six-piece optical module for capturing image are provided. In order from an object side to an image side, the optical lens along the optical axis includes a first lens with refractive power, a second lens with refractive power, a third lens with refractive power, a fourth lens with refractive power, a fifth lens with refractive power and a sixth lens with refractive power. At least one of the image-side surface and object-side surface of each of the six lens elements is aspheric. The optical lens can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. At least one lens among the first to the fifth lenses has positive refractive force. The fifth lens can have negative refractive force, wherein both surfaces thereof are aspheric, and at least one surface thereof has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the fifth lenses. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. At least one lens among the first to the fifth lenses has positive refractive force. The fifth lens can have negative refractive force, wherein both surfaces thereof are aspheric, and at least one surface thereof has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the fifth lenses. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. At least one lens among the first to the fifth lenses has positive refractive force. The fifth lens can have negative refractive force, wherein both surfaces thereof are aspheric, and at least one surface thereof has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the fifth lenses. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. At least one lens among the first to the fifth lenses has positive refractive force. The fifth lens can have negative refractive force, wherein both surfaces thereof are aspheric, and at least one surface thereof has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the fifth lenses. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises five lens elements positioned sequentially from an object side to an image side. Through controlling the convex or concave shape of the surfaces, the refracting power of the lens elements and two parameters to meet an inequality associated with the thickness of the second lens element, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Abstract: An optical lens assembly utilized as part of an electronic device may be configured to provide a compact structure and/or a thin profile for the electronic device while maintaining high resolution, via the use of at least one lens having planar surfaces in partial portions thereof. An optical lens assembly may include at least two lenses arranged from an object side to an image side, where at least one of the at least two lenses includes an object side surface with a planar central region, an image side surface that also has a planar central region and a peripheral region having an aspherical surface. Various embodiments with differing lens arrangements are disclosed.

Abstract: An optical lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The second lens element has refractive power. The third lens element has refractive power. The fourth lens element has refractive power. The fifth lens element with refractive power has an image-side surface being concave in a paraxial region thereof. The sixth lens element with refractive power has an object-side surface being concave in a paraxial region thereof. The seventh lens element with refractive power has an image-side surface being concave in a paraxial region thereof.

Abstract: A compact low-cost imaging lens which provides brightness with an F-value of 2.5 or less and a wide field of view and corrects aberrations properly, meeting the demand for low-profileness. The imaging lens elements are arranged in the following order from an object side to an image side: a first lens with positive refractive power having a convex surface on the object side; a second lens with negative refractive power; a third lens with positive or negative refractive power having at least one aspheric surface; a fourth lens with positive refractive power; a fifth lens as a meniscus double-sided aspheric lens having a concave surface near an optical axis on the image side; and a sixth lens as a meniscus lens having a concave surface near the optical axis on the object side. The both surfaces of the fifth lens have pole-change points off the optical axis.

Abstract: A zoom lens unit includes, in order from an object side to an image side, a first lens group having positive refractive power and a focus function, a second lens group having negative refractive power, which moves when changing a magnification, a third lens group which moves when changing a magnification, and a fourth lens group having positive refractive power, which is fixed when changing a magnification, wherein the following condition (1) is fulfilled: |M2W·M3W·M4W|<0.14 ??(1) where M2W represents an imaging magnification of the second lens group at a wide-angle end, M3W represents an imaging magnification.the third lens group at the wide-angle end, and M4W represents an imaging magnification of the fourth lens group at the wide-angle end.

Abstract: Accommodating (re-focusable) macro lens system which includes first and second individual lenses having first and second optical portions sequentially disposed along an optical axis.

Abstract: A floating image display device includes an image display for displaying a display image; a beam splitter for splitting light emitted from the display image into first light and second light; and a curved retroreflective sheet for retroreflecting the first light to display a floating image based on the display image at a space in air so that the floating image is seen from a predetermined reference position, wherein the image display, the beam splitter and the curved retroreflective sheet are arranged so that the first light traveling from the beam splitter to the curved retroreflective sheet is retroreflected and specularly reflected, a retroreflected light based on the first light travels from the curved retroreflective sheet via the beam splitter to the reference area and a specularly-reflected light based on the first light travels from the curved retroreflective sheet toward outside of the reference area.

Abstract: A light trapping optical structure employing an optically transmissive layer with a plurality of light deflecting elements. The transparent layer is defined by opposing broad-area surfaces extending parallel to each other. The light deflecting elements deflect light propagating transversely through the optically transmissive layer at a sufficiently high bend angle with respect to a surface normal, above a critical angle of a Total Internal Reflection. The deflected light is retained by means of at least TIR in the system which allows for longer light propagation paths through a photoabsorptive layer that may be associated with the optically transmissive layer for an improved light absorption. The light trapping optical structure may further employ a focusing array of light collectors being pairwise associated with the respective light deflecting elements.

Abstract: Lighting arrangement for a diagnostic or surgical microscope has a light source, and the lighting arrangement defining an illuminating beam path. An illumination optics is arranged between the light source and an objective of the microscope which defines an imaging beam path, and in the beam path of the light source at least one deflection element is arranged for coupling in of the illuminating beam path into the imaging beam path. The illumination optics has at least one pancratic system. The lighting arrangement has, in the manner of a Köhler illumination, a collector lens arrangement which is arranged downstream of the light source in the beam direction of the light source, a field diaphragm arranged downstream of the collector lens arrangement, and an auxiliary lens arrangement arranged downstream of the field diaphragm, and the auxiliary lens arrangement has at least one pancratic system.

Abstract: A process is provided for imaging a surface of a specimen with an imaging system that employs a BD objective having a darkfield channel and a bright field channel, the BD objective having a circumference. The specimen is obliquely illuminated through the darkfield channel with a first arced illuminating light that obliquely illuminates the specimen through a first arc of the circumference. The first arced illuminating light reflecting off of the surface of the specimen is recorded as a first image of the specimen from the first arced illuminating light reflecting off the surface of the specimen, and a processor generates a 3D topography of the specimen by processing the first image through a topographical imaging technique. Imaging apparatus is also provided as are further process steps for other embodiments.

Abstract: The present invention relates to an illumination filter system (2) for medical imaging, in particular multispectral fluorescence imaging, as performed e.g. in a microscope (1) or endoscope, such as a surgical microscope, in particular a surgical multispectral fluorescence microscope, comprising a first optical filter (35). The present invention also relates to an observation system (3) for medical imaging, in particular multispectral fluorescence imaging, as performed e.g. in a microscope (1) or endoscope, in particular a multispectral fluorescence microscope, comprising a beam splitter (21) adapted to split a light image (13) into a first light portion (16, 17) along a first light path (18) and a second light portion (20) along a second light path (19).

Abstract: A confocal microscope apparatus includes an image acquisition unit configured to obtain a first all-in-focus image of each of a plurality of measurement visual field areas constituting a measurement target area in a brightness setting in accordance with the corresponding measurement visual field area, and a stitched image constructor configured to construct a stitched image on the basis of a plurality of second all-in-focus images. The second all-in-focus images are obtained through conversion of the plurality of first all-in-focus images obtained by the image acquisition unit so that the images become closer to a plurality of reference all-in-focus images. The plurality of reference all-in-focus images are obtained when the plurality of measurement visual field area are captured in a brightness setting serving as a reference.

Abstract: Non-telecentric in image space optical objective dimensioned to operate as part of intravascular endoscope probe and including first and second groups of lens elements (separated by an aperture stop) each of which has negative optical power. The first group of lens elements includes a first meniscus lens with a positive dioptric power and a first optical doublet. The second group of lens elements includes a sequence of second and third optical doublets and a second meniscus lens that follows the third optical doublet. At least one of the first and second groups of lens elements includes an aspheric refractive surface, thereby reducing distortion down to under 0.25% for field angles up to at least 40 degrees.

Abstract: There is provided an endoscope objective optical system having a thin diameter, a wide in-water angle of view, a small variation in the angle of view, and a short overall length of the optical system. The endoscope objective optical system includes in order from an object side, a front group GF having a negative refractive power, an aperture stop, and a rear group GR having a positive refractive power, wherein the front group includes a first negative lens L1 and a second negative lens L2, and the following conditional expressions (1), (2), (3?), and (4) are satisfied: 1<Iw/ft<1.8??(1), 4<Lt/Iw<9.5??(2), 1.49?Lsf/ft?2.30??(3?), and 0.38<?La/Lsf<0.6??(4).

Abstract: There is provided an endoscope objective optical system with a small size and a high image quality, and in which, an adequate space for disposing a visual-field direction converting element is secured. The endoscope objective optical system, comprising in order from an object side: a first group having a negative refractive power; an aperture stop; and a second group having a positive refractive power, wherein the first group includes in order from the object side, a first lens having a negative refractive power and a visual-field direction converting member, and the second group includes in order from the object side, a second lens having a biconvex shape and a cemented lens in which a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented in this order, and the endoscope objective optical system satisfies the following conditional expressions (1), (2), (3), and (4) 2.4?d1/f?4.6 ??(1) 1.85?f2/f?2.6 ??(2) ?50?r21/r22??0.4 ??(3) 2.

Abstract: There is provided an objective optical system for endoscope which is small-sized, and has a favorable optical performance and fast F-number. An objective optical system for endoscope comprises in order from an object side: a first lens having a negative refractive power; a second meniscus lens having a positive refractive power with a convex surface thereof directed toward the object side; an aperture stop; a third lens having a biconvex shape, and a cemented lens having a positive refractive power as a whole, in which a fourth lens having a biconvex shape and a fifth lens having a negative refractive power are cemented, wherein the objective optical system for endoscope satisfies the following conditional expressions (1), (2), and (9). ?3?f1/Ih??1.2??(1) 0.25?L3_5/L?0.7??(2) 0.2?r2/r3?0.

Abstract: A wavelength tunable gain medium with the use of micro-electromechanical system (MEMS) based Fabry-Perot (FP) filter cavity tuning is provided as a tunable laser. The system comprises a laser cavity and a filter cavity for wavelength selection. The laser cavity consists of a gain medium such as a Semiconductor Optical Amplifier (SOA), two collimating lenses and an end reflector. The MEMS-FP filter cavity comprises a fixed reflector and a moveable reflector, controllable by electrostatic force. By moving the MEMS reflector, the wavelength can be tuned by changing the FP filter cavity length. The MEMS FP filter cavity displacement can be tuned discretely with a step voltage, or continuously by using a continuous driving voltage. The driving frequency for continuous tuning can be a resonance frequency or any other frequency of the MEMS structure, and the tuning range can cover different tuning ranges such as 30 nm, 40 nm, and more than 100 nm.

Abstract: Technologies and implementations for reflective roofs are generally disclosed.

Abstract: A general method is provided for electronically reconfiguring the internal structure of a solid to allow precision control of the propagation of wave energy. The method allows digital or analog control of wave energy, such as but not limited to visible light, while maintaining low losses, a multi-octave bandwidth, polarization independence, large area and a large dynamic range in power handling. Embodiments of the technique are provided for large-angle beam steering, lenses and other devices to control wave energy.

Abstract: Phosphor elements comprising phosphors in a host material having a phosphorescence-emitting surface with surface nanostructures are disclosed. Phosphor wheels having such phosphor elements, methods of making such phosphor elements, and methods of using such phosphor elements are also disclosed.

Abstract: The mirror group is formed by a monolithic frame bent along a bending line and including a first and a second supporting portions carrying, respectively, a first and a second chips forming two micromirrors made using MEMS technology. The first and second supporting portions are arranged on opposite sides of the bending line of the frame, angularly inclined with respect to each other. The mirror group is obtained by separating a shaped metal tape carrying a plurality of frames, having flexible electric connection elements. After attaching the chips, the frames are precut, bent along the bending line, and separated.

Abstract: A head mounted image display apparatus including an image projection section that forms an image and projects the image, a display section that displays the image projected by the image projection section, a control section that controls the image formation performed by the image projection section, a frame member that supports the display section, and a case member that is attached to the frame member and accommodates the image projection section and the control section, wherein the control section is located below the image projection section, and the case member includes an inner case that has a first rib surrounding the circumference of the control section and is located between the image projection section and the control section and an outer case that is attached to the frame member and covers the image projection section and the control section and further covers the inner case.

Abstract: A curved lens protector can include a tempered glass body having a self-supporting x-y axis curve with a concave inner surface and a convex outer surface opposite the inner surface. The tempered glass body can have an outer boundary of a predetermined shape to substantially match and fit with respect to an inner boundary of a lens holder portion of a predetermined lens frame. The tempered glass body can be configured for attachment to a predetermined curved lens without the use of an adhesive.

Abstract: A hand-held therapeutic laser apparatus with a special opto-mechanical construction, which enables changeability of a front collimating lens to create different effective laser apertures. A smaller effective aperture has a comparatively higher radiant flux density for treatment of a small area that requires a higher energy dose, while a larger effective aperture facilitates treatment of a large area at a relatively reduced radiant intensity.

Abstract: The wide angle optical system includes in order from a side of an object in front, a first lens group having a negative refractive power, a second lens group having a catadioptric optical element, an aperture stop, and a third lens group having a positive refractive power, and the catadioptric optical element has a first surface, a second surface, and a third surface, and the first surface has a first transmitting surface and a first reflecting surface, the second surface has a second transmitting surface and a second reflecting surface, and the third surface has a third transmitting surface, and the third transmitting surface is a side surface of a circular truncated cone, and the following conditional expressions (1), (2), and (3) are satisfied: ?p<?n??(1), |?p|<|?n|??(2), and 90°??k<?/2??(3).

Abstract: Head-worn computers may include an optical chassis mechanically configured to provide a stable optical mounting reference plane and a plurality of image source reference planes, a first image source mounted on a first of the plurality of image source reference planes and configured to project first image light through a first hole in the stable optical mounting reference plane, a second image source mounted on a second of the plurality of image source reference planes and configured to project second image light through a second hole in the stable optical mounting reference plane, and an outer frame configured to hold the optical chassis such that, when worn by a user, the first and second image light is aligned with the eyes of the user.

Abstract: An imaging and display module for a head-worn computer provides displayed images to a user including a plurality of optical components and a plurality of electrical components that provide displayed images to a left eye and a right eye of the user, one or more cameras, and a rigid chassis comprising a box structure with high thermal conductivity sections, wherein the plurality of optical components are rigidly mounted to the chassis so that the displayed images are rigidly aligned relative to the cameras and to the left and right eyes of the user and the plurality of electrical components are mounted to the sections with high thermal conductivity to dissipate heat.

Abstract: On the basis of information detected from a peripheral situation detecting section and information from an automatic driving support section, a display control section generates image data in which marks for driving support of an own vehicle are drawn so as to be superposed on a forward situation diagram that shows a situation at a front side. Further, from information detected by an eye detecting section and from the image data, the display control section sets a vanishing point in accordance with a height position of eyes and computes a display image. Moreover, on the basis of the information detected by the eye detecting section, the display control section causes a display image to be displayed on the front windshield glass by a HUD such that the vanishing point is set in accordance with the height position of the eyes.

Abstract: A head up display for a vehicle according to an embodiment includes a display panel configured to emit an image light; a polarized light plate configured to make the image light emitted from the display linearly polarized; a reflective mirror configured to reflect the image light onto a windshield of a vehicle; a polarized light reflective mirror configured to be disposed to face the reflective mirror; and a phase delay mirror configured to convert a phase of the light inputted from the polarized light plate and reflect the converted phase to the polarized light reflective mirror, and to convert a phase of the light reflected from the polarized light reflective mirror and reflect the converted phase to the polarized light reflective mirror, thereby minimizing a width in the forward and backward direction.

Abstract: A display system of a vehicle includes a display device disposed in the vehicle and operable to display heads up information for viewing by a driver of the vehicle. The display device includes a mirror, a display screen and a cooling device. The mirror is pivotally mounted at a base plate and is pivotable via a pin of a mounting arm of the mirror moving along a spiral groove of a gear element when the gear element is rotated. The pin is urged towards a side wall of the spiral groove to limit play of the mirror relative to the base plate.

Abstract: The present invention is compact and inexpensive, has good light efficiency, and enables a display image having a plurality of display distances to be displayed. A display emits projection light for displaying a display image at a predetermined position, and an image formation position adjusting mirror receives the projection light emitted from the display, performs conversion into a plurality of first projection light and second projection light that have different image formation distances by changing the image formation distance of the projection light that is at least part of the incident projection light, and reflects the first projection light and the second projection light to project the first projection light and the second projection light onto a first screen and a second screen.

Abstract: The embodiments of the present invention provide a head-up display, a head-up display method and a vehicle-mounted display device. The head-up display includes: a digital light processing unit used for generating an imaging beam; a reflector unit used for reflecting the imaging beam to a reflective surface cooperating with the head-up display to form an image; and an adjusting unit used for adjusting a direction of the reflector unit, thereby providing a desired depth to the image. In the embodiments of the invention, by presenting an image with a desired depth, the displayed information can be fused together with the environment. In this way, information can be presented in the best mode, visual fatigue of the driver can also be effectively avoided, thereby avoiding danger.

Abstract: An image generation apparatus for generating an image includes a light source device; an optical deflection device to deflect laser beam from the light source device to a scanned face arid a light detector; a light quantity adjustment device including a member disposable on a light path of the laser beam between the light source device and the optical deflection device; an emission light intensity adjustment unit to adjust emission light intensity of the light source device; and a controller to set a first adjustment target value of emission light intensity and an adjustment target value of light quantity when laser beam is deflected to the scanned face based on target luminance of the image, and a second adjustment target value of emission light intensity when laser beam is deflected to the light detector based on an adjustment target value of light quantity and detection sensitivity of the light detector.

Abstract: The invention relates to a housing for a head-up display of a motor vehicle, which housing has an inner wall that at least partially delimits an internal space for an imaging projection device to project a virtual image in a beam path onto a reflection surface in an internal space of the motor vehicle. The housing is characterized by at least one reflective deflection region of the internal wall to deflect the beam path of the imaging projection device. The deflection region may have a metallized or metallizing layer which is formed via the application of a metallizing, amorphous substance or material onto a surface of a base body of the inner wall, said surface facing toward the internal space. The invention furthermore relates to a corresponding head-up display, a correspondingly embodied motor vehicle, and a method to provide a housing according to the invention.

Abstract: A near eye or heads up display system includes a display engine, at least two optical waveguides, and a respective coating on at least one of the major surfaces of at least one of the waveguides. At least one such coating has a low reflectance for light within a specific wavelength range for the waveguide and incident on a major surface of the waveguide on which the coating is located at an angle below a low threshold angle relative to a normal, and has a high reflectance for light within the specific wavelength range for the waveguide that is incident on the major surface on which the coating is located at an angle above a high threshold angle relative to the normal.

Abstract: A waveguide display includes a light source, a conditioning lens assembly, a scanning mirror assembly, and a controller. The light source includes a plurality of source elements that are configured to emit image light in accordance with scanning instructions. The conditioning lens assembly transmits conditioned light based in part on the image light. The scanning mirror assembly scans the conditioned image light to particular locations as scanned image light in accordance with scanning instructions. The output waveguide includes an input area and an output area, receives the scanned image light emitted from the scanning mirror assembly at the input area, and outputs the expanded image light from a portion of the output area based in part on a direction of the expanded light output from the scanning mirror assembly. The controller generates the scanning instructions and provides the scanning instructions to the light source and the scanning mirror assembly.

Abstract: A holographic see-through optical device, a stereoscopic imaging system including the same, and a multimedia head mounted system are provided. The holographic see-through optical device includes a micro display; a relay optical system, which relays an image generated by the micro display; at least one waveguide comprising at least two portions having different thicknesses or different refractive indexes; at least one first holographic optical element, which is arranged at one of the two portions; and at least one second holographic optical element, which is arranged at the other one of the two portions.